Method of covering books with heat sealable thermoplastic material

ABSTRACT

A rectangular slot is cut in one layer of a folded covering material. The opened covers of a book are inserted between the layers, with the pages extended through the slot. Then the edges of the layers are sealed to form a cover.

United States Patent [19] Saurs 1 1 Jan. 30, 1973 [54] 3 0 et a WITHYHEAT SEALABLE 1,995,076 3/1935 Perryman ..156/261 THERMOPLASTIC MATERIAL 3,198,685 8/1965 Kopito et a1 ..l56/583 [76] Inventor: Richard Saul-S Richmond, 2,362,168 11/1944 Stokes ..l98/184 22 F116d: July 30, 1970 H pp NO 64 907 FOREIGN PATENTS OR APPLICATIONS 1,360,285 3/1963 France 1/34 Related U.S. Application Data [62] Division 61 S61. NO. 748,869, July 30, 1968, aban- 'F 'Y Bmche d0ned Asszstant Examiner-D. A. Bent Attorney-Glenn, Palmer, Lyne, Gibbs and Thompson [52] U.S.Cl. ..l56/25l,281/34,264/23O '15 11 rm. (:1. ..Bl8b 31/20 1571 ABSTRACT 1 1 Field of Search 13,85, i i A rectangular slot is cut in one layer of a folded coveri ing material. The opened covers ofa book are inserted 193/184 between the layers, with the pages extended through the slot. Then the edges of the layers are sealed to [56] References Cited form a cover.

UNITED STATES PATENTS 7 Claims, 3 Drawing Figures 3,071,819 1/1963 Harrison ..264/230 METHOD OF COVERING BOOKS WITH HEAT SEALABLE THERMOPLASTIC MATERIAL CROSS-REFERENCE TO RELATED APPLICATION This application is a division of application Ser. No. 748,869, filed July 30, l968, now abandoned.

BACKGROUND OF THE INVENTION Many books are protected by using suitable coverings fastened around theirouter covers. However,

the previously proposed coverings are comparatively complicated and expensive and require expensive machines and/or methods of installation to install such coverings in position around their associated books.

SUMMARY BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing shows an exemplary embodiment of this invention, in which FIG. 1 is a perspective view with parts in section and parts brokenaway illustrating a number of books in various stages of having an outer covering installed thereon utilizing an exemplary apparatus and method of this invention; 1

FIG. 2 is a view on the line 22 of FIG. 1 particularly illustrating a cutting board supported in position between an upper and a lower layer of a center-folded covering material to enable cutting a rectangular slot in the upper layer of the center-folded covering material and wherein such rectangular slot is adapted to receive the pages of an associated book therethrough; and

FIG. 3 is a fragmentary view with partsin section and parts broken away particularly illustrating one of the leg portions of an L-shaped heat-sealing and cutting bar comprising the apparatus of this invention.

DESCRIPTION OF ILLUSTRATED EMBODIMENT Reference is now made to FIG. 1 of the drawing which illustrates an exemplary apparatus and method of this invention which is designated generally by the reference numeral and of a plurality'of books each designated by the same reference numeral 21 and shown at various stages of fastening an outer covering in position against the outer covers 22 of each associated book 21. The completed outercovering after being fastened in position by the improved apparatus and method of this invention is shown in the lower right hand corner of FIG. 1 and designated generally by the reference numeral 23 and comprises a lower layer 24 and an upper layer 25 which are foldably fastened along a common edge 26.

The upper layer 25 has a rectangular slot which receives the central portion, shown'as held-together pages 31 in this example of the invention, of an associated book 21 therethrough and a substantially U- shaped seal 33 comprises the outer periphery of the outer covering 23 and has a bight 34 which is arranged substantially parallel to the common edge 26 and a pair of leg portions 35 and 36 extending from the terminal ends of the bight 34 and the leg portions 35 and 36 have their terminal ends intersecting the common edge 26. The rectangular slot has a width which is closely correlated to the total thickness of the pages of the book 20 thereby assuring the covering 23 is held in position in an optimum manner and assuring the entire inside surface of the covers 22 is protected. Thus, it will be appreciated that the outer covering 23 is of utmost simplicity and suitably held in position around an associated book by the common edge 26 and U-shaped seal 33.

Having described the outer covering 23 provided for each book 21 the detailed description will now proceed with a detailed description of the exemplary apparatus for and method of installing the covering 23 around the outer covers 22 of each book 21, see FIGS. 1 and 2. The apparatus 20 comprises a support shown in the form of a spindle 40 for supporting a roll 41 of covering material for unobstructed unwinding rotation. The spindle 40 may be suitably supported so that its axis and hence the roll of covering material is supported in a horizontal plane; Further, the spindle 40 may be supported on an associated portion of the frame structure comprising the apparatus 20.

The covering material may be any suitable covering material such as a web of sheet-like covering material 42 which in this example of the invention is a heatsealable and heatshrinkable plastic material and is center-folded and suitably wound to define the roll 41. The plastic material 42 may also be a transparent plastic material to enable easy viewing of the outer covers 22 of an associated covered book 21.

The covering material 42 in this example of the invention is center-folded so as to define a lower layer and an upper layer foldably fastened along a common edge. For simplicity of description and understanding the lower layer, upper layer, and common edge of the center-folded covering material 42 will also be designated by the reference numerals 24, 25, and 26 to correspond to similar layers comprising the completed outer covering 23 of a covered book 21.

The apparatus 20 has a horizontal conveyor 44 which is provided for supporting and moving the covering material 42 along the apparatus 20 and in a manner as will be described in more detail subsequently. The horizontal conveyor 44 is preferably in the form of an endless belt conveyor which is supported on a pair of spaced rollers 45 and 46 so that a top load carrying portion 50 of the conveyor 44 is arranged in a horizontal plane. The supporting rollers 45 and 46 of the belt conveyor 45 are suitably supported on a portion of the frame structure comprising the apparatus 20 and the roller 46 has a shaft 51 extending from one end thereof which is driven by an electric motor 52 through a gearbox assembly 53 operatively connected to the shaft 51 so as to enable moving of the belt conveyor 44 in a known manner. The electric motor 52 is supplied with electrical power from a suitable power source.

The belt conveyor 44 has a plurality of apertures extending therethrough and such apertures may be mechanically formed in a substantially fluid-impervious belt conveyor 44 or such apertures may be defined by making the conveyor 44 from a material which is porous and is inherently provided with a plurality of comparatively small apertures extending perpendicularly therethrough. In this example of the invention, this latter type of belt conveyor is shown in the drawing and the above-mentioned apertures are designated generally by the reference numeral 54 and presented as a granular showing in the belt.

The apparatus 20 has a vacuum device 55 which is suitably supported beneath and against the lower surface of the top load-carrying portion 50 of the conveyor 44 In fact, the top wall 57 of the device 55 provides vertical support for the load-carrying portion 50. The vacuum device 55 has an enclosed vacuum chamber indicated at 56 which has the general shape of a parallelepiped and the vertical height of the device 55 is substantially less than the diameter of the rollers 45 and 46 so that the vacuum device 55 is easily supported between the top load-carrying portion 50 of the belt conveyor 44 and its lower portion 61.

The vacuum device 55 has a line 62 extending outwardly therefrom which is suitably connected to a vacuum pump and the device 55 has a plurality of openings 63 in its top wall 57 so that upon applying a vacuum to the line 62 a suction is applied through the openings 63 and through the belt conveyor 44 which causes the lower layer 24 of the covering material 42 to be held tightly against the belt conveyor 44 as it is moved across the vacuum device 55 and for a purpose which will be apparent hereinafter.

The lower layer 24 is caused to adhere by vacuum against the top surface of the load-carrying portion 50 of the belt conveyor 44 and the vacuum exerts a sufficient holding force against the covering material 42 which enables the covering material 42 to be unwound from its supply roll 41 merely by driving the belt conveyor 44 in its endless path.

The apparatus 20 has a cutting board 65 which is supported above and adjacent to one end portion of the belt conveyor 44 so that the cutting board extends between the lower layer 24 and upper layer 25 of the covering material 42. The cutting board 65 may be in the form of a stationary board which has the lower layer 24 and the upper layer 25 of the covering material passed on opposite sides thereof to enable the upper layer 25 to be cut in a manner to be subsequently described, or such cutting board 65 may be an easily movable board of the type which is inserted in position and suitably supported only when it is needed.

The cutting board 65 may be made of any suitable material, either metallic or nonmetallic, and is preferably of the type which may have a cutting knife urged thereagainst repeatedly without substantial damage thereto or marring thereof.

The apparatus 20 includes a cutting knife 70 which is suitable supported for movement toward and away from the cutting board 65. The cutting knife is adapted to be urged against the upper layer 25 of the covering material 42 so as to sandwich such upper layer against the top surface 71 of the cutting board and thereby cut a rectangular slot in the upper layer 25 and such rectangular slot will also be designated by the reference numeral 30 inasmuch as it defines the slot 30 previously described in connection with the description of the completed outer covering 23. The rectangular slot 30 is cut in the upper layer 25 so that it extends completely across such upper layer and is arranged substantially perpendicular to the common edge 26 of the lower layer 25 and upper layer 25.

The cutting knife may be of any suitable construction; however, in this example of the invention the cutting knife has a substantially U-shaped heated cutting edge 72 which is particularly adapted to be urged against the plastic covering material 42 to sever the rectangular opening 30 therein. Also, the terminal outer end of the knife 70 may have a structural portion 73 which provides added rigidity for the outer ends of the U-shaped cutting edge 72.

With the provision of a rectangular slot 30 in the upper layer 25 of the plastic material 42 it is a simple matter to insert the book 21 to be covered in position simply by holding the pages 31 together in a substantially vertical plane so that its covers 22 are positioned substantially perpendicular to the vertical plane and in this example of the invention the lower surfaces of the covers 22 are supported by the belt conveyor 44 in a horizontal plane corresponding to the horizontal plane of the belt conveyor 44. The book 21 is moved from the dotted line position illustrated at 75 in FIG. 1 to the solid line position at 76 shown immediately above the central portion of the vacuum device 55. The free outer ends of the lower layer 24 and upper layer 25 are then sealed together so as to define the previously mentioned U-shaped seal 33 and the heat-sealing technique used to provide the heat seal 33 will be described in detail subsequently.

The lower layer 24 of the covering material 42 is held by the vacuum device 55 against the top load carrying portion 50 of the belt conveyor 44 as previously explained. It is then a simple matter to lift the upper layer 25 of the covering material 42 on either side of the rectangular slot 30 so that the covers 22 of a particular book 21 may be inserted in position from the dotted line position 75 to the solid line position 76.

After a particular book 21 is inserted in position as illustrated at 76 the held-together pages 31 of such book may be held together by hand so that the free outer ends of the layers 24 and 25 may be sealed together as by heat sealing. During and after such heat sealing the held-together pages 31 are maintained in a vertical position in any suitable manner and the book 21 with its outer covers now covered with the covering material 42 is moved to a shrinking device designated generally by the reference numeral 80 and such outer covering is shrunk in position therearound to define the completed outer covering 23.

To facilitate the movement of the book 21 with its pages 31 held together and maintained in a vertical position the apparatus 20 may include a holding device 82. The device 82 comprises a substantially U-shaped portion 83 having a bight 84 which corresponds in length to the thickness of the held-together pages 31 and the device 82 has a pair of substantially parallel arms each designated by the reference numeral 86 extending toward an associated cover 22 of the book and a leg 87 extending from the terminal outer end of each arm 86 and engaging an associated outer cover 22 to hold the pages 31 together in an upright manner and facilitate heat sealing the free outer ends of the lower layer 24 and the upper layer 25. The device 82 also holds the pages 31 in an upright manner as the covered book 22 is moved by another belt conveyor 90 through the shrinking device 80 which may be in the form of a shrinking oven or tunnel 80.

Each device 82 may also have an arcuate portion 91 defining the terminal lower end of each of its legs 87 and the arcuate portion 91 assures that as each book is moved through the shrinking oven 80 and the plastic material is shrunk in position therearound to define the outer covering 23 the upper layer of the covering material is free to shrink tightly along the inside surface of the outer covers 22 without being obstructed in a detrimental manner by the device 82.

Fora given size book 22 the total width across its outer covers is generally known and does not vary appreciably from one book to the next. The U-shaped cutting knife 70 may be operated in a substantially semi-automatic manner as determined by the amount of material unwound from the roll 41 of plastic covering material 42 so that the rectangular slots are placed in the upper layer 25 at the desired intervals and so that a maximum number of-books may be covered by the covering material 42 without waste.

The apparatus 20 also has a sealing device 92 for sealing the free outer ends of the layers 24 and 25 after inserting the covers 22 'of a book between such layers with pages 31 of the book held together and extended through the associated slot 30. The sealing device 92 comprises a substantially L-shaped sealing and cutting bar which is suitably supported for movement toward and away from the top load carrying portion 50 of the belt conveyor 44, and in particular the L-shaped bar is adapted to be moved against and away from an L-- shaped backup board 98 which is supported in a fixed position immediately above the discharge end portion of the belt conveyor 44.

The L-shaped sealing bar has one leg 93 which is arranged substantially parallel to the common edge 26 and is adapted to heat seal each book 22 along the full width indicated at 94 of both of its interconnected covers. The L-shaped sealing bar has a second leg 95 which is arranged perpendicular to the common edge 26 and the leg 95 simultaneously heat seals a comparatively wide rectilinear strip 96 arranged perpendicular to the common edge 26 and between one book shown at 100 still being carried on the belt conveyor 44 and for another book shown at 101 as moving onto the belt conveyor 90. The leg 95 of the L-shaped bar 92 also has a cutting edge 102, see FIG. 3, which bisects the strip 96 upon being urged against the backup board 98 to effectively release the now completely covered book 22 from the roll 41 and allow such book to be moved to the shrinking oven 80 by the belt conveyor 90.

The leg portion 95 of the L-shaped heat-sealing bar 92 is constructed so that a main substantially planar lower surface 103 of such bar engages the plastic material 42 to define the strip 96. With further urging of the bar 92 and hence leg portion 95 tightly against the top surface 99 of the backup board 98 the comparatively sharp edge 102 is extended outwardly and is effective to bisect the strip 96 in the manner previously mentioned.

Once the strip 96 is bisected by the cutting edge 102 the trailing sealed portion of such strip defines the sealed strip portion 35 of the U-shaped seal 33 for the book shown at 100 while the leading sealed portion defines the sealed strip portion 36 of the book shown at 101.

The sharp cutting edge 102 is also a heated edge and the top surface 99 of the backup board 98 is made of a suitable heat resistant material which enables easy cutting and heat sealing without damage thereto.

The book 21 with a plastic covering now heat sealed around its outer covers 22 is moved by the belt conveyor 90 to the heat shrinking oven and the device 82 is utilized to hold the pages 31 in an upright manner. The belt conveyor is moved at the same speed as a belt conveyor 44 and the belt conveyor 90 may be of a conventional construction and suitably carried by a plurality supporting rollers 105 only one of which is illustrated in the drawing. However, it will be appreciated that it may be desirable in some applications of this invention to utilize only the belt conveyor 44 which has its downstream portion extended so as to extend through the oven 80 to enable heat sealing of the plastic covering material around the outer covers 22 of the book 21 and define the completed outer covering 23.

Although in this example of the invention the heat shrinking of the plastic covering material 42 is shown as being achieved in an oven 80 it will be appreciated that such heat shrinking could be achieved in any other suitable manner. For example, the book could be moved past a heat shrinking station and one or more nozzles could be utilized to direct a blast of heated air against the plastic material to heat shrink such material.

Having described the operation of the apparatus and method of this invention in detail, a brief general description will now be made to highlight the simplicity with which a plurality of books may be successively covered in a simple and efficient manner and the action a at a plurality of locations along the apparatus 20 will be generally described.

l Thus, it is seen that a leading end portion of the center folded plastic covering material 42 is unwound from its supply roll 41 and onto the belt conveyor 44. The vacuum device 55 is in operation and vacuum applied by such vacuum device through the apertures 54 of the belt conveyor 44 is sufficient to enable the covering material 42 to be unwound from its supply roll 41 merely by operating the belt conveyor 44.

The vacuum device holds the lower layer 24 of the plastic material 42 tightly against the top load-carrying portion 50 of the belt conveyor 44 and such lower layer 24 is held positioned beneath a cutting board 65 with the top layer 25 being moved over the top surface 71 of such cutting board.

The cutting knife 70 is moved into cutting position and its U-shaped cutting edge 72 cuts a rectangular slot 30 in the upper layer 25 of the plastic material 42.

At a position substantially above the central portion of the belt conveyor 44 the upper layer 25 of the plastic covering material 42 is lifted in any suitable manner as by hand, for example, and a book 21 is inserted so that its covers 22 are sandwiched between the lower layer 24 and upper layer 25. The book 21 is moved essentially from the dotted line position 75 to the solid line position 76 illustrated in FIG. 1 of the drawing. The lifting of the upper layer 25 is achieved in a simple manner because as previously indicated the lower layer 24 is held tightly against the top load carrying portion 50 of the belt conveyor 44 by the vacuum device 55. The U- shaped holding device 82 is then inserted in position to hold the pages 31 of such book in an upright manner and the continued movement of the belt conveyor 44 moves the book to the heat-sealing and severing position under the substantially L-shaped bar 92.

The L-shaped bar 92 is lowered in position so that its leg 93 seals completely along the full width of both of its covers 22 and its leg 95 defines the sealed and comparatively wide rectilinear strip 96 which is arranged perpendicular to the common edge 26. Immediately after the leg portion 95 defines the wide sealed strip 96 such strip is severed by the knife edge portion 102 comprising the leg portion 95 to define the sealed str'ip portion 36 for the book shown at 101 and the sealed strip portion 35 for the book shown at 100 whereupon the book at 101 is now effectively released from the supply roll 41 of covering material 42.

Each book 21 is now moved by the belt conveyor 90 to the heat-shrinking oven 80 and the plastic covering material 42 is shrunk in position therearound to define the outer covering 23 and it will be seen that such outer covering has a lower layer 24 and an upper layer 25 which are foldably fastened together along a common edge 26; and, the heat-sealing is achieved to define a substantially U-shaped seal 33 around the covers 22 of each book 21.

The knife 70 and L-shaped bar 92 may be moved automatically in timed sequence with the belt conveyor 44. Also, the L-shaped bar 92 may be moved against the upper layer 25 so as to heat seal such upper layer against the lower layer 24 immediately adjoining the terminal ends of the outer covers 22 of each book 21. It will also be appreciated that the cutting of slot 30 and heat sealing of the free ends of layers 24 and 25 may also be achieved manually without resorting to movement of the knife 70, the L-shaped bar 92, and the conveyor 44 in timed sequence. Further, the cutting knife; 70 and L-shaped bar 92 may also be moved toward and away from the plastic covering material 42 utilizing suitable actuators which may be power driven in any suitable manner.

The detailed description presented above and the presentation in the drawing may tend to emphasize that this invention is mainly applicable to a book having a central portion defined by pages integrally fastened therein. However, it is to be understood that the covering of this invention and the apparatus for and method of providing same is fully applicable to all types of book-like articles and books which need not necessarily have pages integrally fastened therein, such as notebooks, for example.

In the case ofa notebook, the central portion may be defined by projection means integrally fastened therein and such projection means may comprise any desired type of fastening device used to fasten loose articles, such as pages, in the notebook. The width of the rectangular slot 30 in the upper layer 25 of the covering for a notebook is closely correlated to the width of the projection means or integral fastening device.

The plastic covering material 42 may be in the form of any suitable plastic material which is heat-scalable and heat-shrinkable. Two examples of such material are polyvinyl chloride and polyethylene.

While a present exemplary embodiment of this invention, and method of practicing the same, have been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. A method of covering the outer covers of a book comprising the steps of, center folding a heat-scalable plastic covering material to define an upper and a lower overlapped layer having a common edge, cutting a rectangular slot in one of said layers, holding the central portion of a book substantially in one plane so that its covers are positioned substantially in a perpendicular plane lifting said upper layer on both sides of said rectangular slot while holding said lower layer against a planar supporting surface to define a space between said layers, inserting said covers into said space between said layers with aid central portion extending through said slot by moving said covers in a plane substantially parallel to said planar supporting surface, and heat sealing the free outer edges of said layers together to fasten and hold said covering material in position.

2. A method as set forth in claim 1 in which said book has pages integrally fastened therein and defining said central portion and said holding step comprises holding said pages together and in said one plane.

3. A method as set forth in claim 1 in which said cutting step comprises the steps of supporting a cutting board having a top planar surface between said layers and urging a heated cutting knife against said one layer sandwiching it against said top planar surface of said cutting board to form said rectangular slot.

4. A method as set forth in claim 1 comprising the further step of heat shrinking said plastic material tightly against said covers after heat sealing said free outer ends together.

5. A method of covering the outer covers of books comprising the steps of, center folding a web of a heatsealable plastic covering material to define an upper and a lower overlapped layer having a common edge, winding said center-folded plastic material to define a roll thereof, unwinding a portion of said center-folded plastic material from said roll onto a horizontal conveyor and holding said lower layer tightly against said conveyor, cutting a rectangular slot in said upper layer, said cutting step comprising supporting a cutting board having a top planar surface said conveyor and between said layers and urging a heated cutting knife against said upper layer sandwiching it against said top planar surface of said cutting board to cut said rectangular slot, holding the central portion of a book to be covered substantially in one plane so that its covers are positioned substantially in a perpendicular plane, lifting said upper layer on both sides of said rectangular slot while holding said lower layer against said conveyor to define a space between said layers, inserting said covers into said space between said layers with said central portion extending through said slot by moving said covers in a plane substantially parallel to said conveyor, and sealing the free outer edges of said layers together to fasten and hold said covering material in position around said book.

material from said roll onto a horizontal conveyor and holding said lower layer tightly against said conveyor comprises applying a vacuum perpendicularly through a top load-carrying portion of said conveyor to hold said lower layer thereagainst. 

1. A method of covering the outer covers of a book comprising the steps of, center folding a heat-sealable plastic covering material to define an upper and a lower overlapped layer having a common edge, cutting a rectangular slot in one of said layers, holding the central portion of a book substantially in one plane so that its covers are positioned substantially in a perpendicular plane lifting said upper layer on both sides of said rectangular slot while holding said lower layer against a planar supporting surface to define a space between said layers, inserting said covers into said space between said layers with aid central portion extending through said slot by moving said covers in a plane substantially parallel to said planar supporting surface, and heat sealing the free outer edges of said layers together to fasten and hold said covering material in position.
 1. A method of covering the outer covers of a book comprising the steps of, center folding a heat-sealable plastic covering material to define an upper and a lower overlapped layer having a common edge, cutting a rectangular slot in one of said layers, holding the central portion of a book substantially in one plane so that its covers are positioned substantially in a perpendicular plane lifting said upper layer on both sides of said rectangular slot while holding said lower layer against a planar supporting surface to define a space between said layers, inserting said covers into said space between said layers with aid central portion extending through said slot by moving said covers in a plane substantially parallel to said planar supporting surface, and heat sealing the free outer edges of said layers together to fasten and hold said covering material in position.
 2. A method as set forth in claim 1 in which said book has pages integrally fastened therein and defining said central portion and said holding step comprises holding said pages together and in said one plane.
 3. A method as set forth in claim 1 in which said cutting step comprises the steps of supporting a cutting board having a top planar surface between said layers and urging a heated cutting knife against said one layer sandwiching it against said top planar surface of said cutting board to form said rectangular slot.
 4. A method as set forth in claim 1 comprising the further step of heat shrinking said plastic material tightly against said covers after heat sealing said free outer ends together.
 5. A method of covering the outer covers of books comprising the steps of, center folding a web of a heat-sealable plastic covering material to define an upper and a lower overlapped layer having a common edge, winding said center-folded plastic material to define a roll thereof, unwinding a portion of said center-folded plastic material from said roll onto a horizontal conveyor and holding said lower layer tightly against said conveyor, cutting a rectangular slot in said upper layer, said cutting step comprising supporting a cutting board having a top planar surface said conveyor and between said layers and urging a heated cutting knife against said upper layer sandwiching it against said top planar surface of said cutting board to cut said rectangular slot, holding the central portion of a book to be covered substantially in one plane so that its covers are positioned substantially in a perpendicular plane, lifting said upper layer on both sides of said rectangular slot while holding said lower layer against said conveyor to define a space between said layers, inserting said covers into said space between said layers with said central portion extending through said slot by moving said covers in a plane substantially parallel to said conveyor, and sealing the free outer edges of said layers together to fasten and hold said covering material in position around said book.
 6. A method as set forth in claim 5 in which said sealing step comprises heat sealing said free outer ends together and comprising the further steps of heat shrinking said plastic material tightly against said covers after heat sealing said free outer ends together. 